A Preliminary Study on the Influence of Cannabis and Opioid Use on Weight Loss and Mental Health Biomarkers Post-weight Loss Surgery

Purpose: A subpopulation of weight loss surgery (WLS) patients endorse cannabis and/or opioid use; however, impact on post-WLS anxiety and depression is unclear. This study examined the influence of the independent and combined use of cannabis and opioids on (1) depression and anxiety, (2) duodenum serotonin and cortisol, and (3) total percent weight loss.

Materials and methods: A cross-sectional analysis was conducted among patients (N = 18) who had biomarkers of serotonin and cortisol collected from the duodenum during WLS. Cannabis and opioid use was determined by self-reported lifetime, past-year, and past 30-day use. The Beck Anxiety Inventory and Depression Inventory-II assessed depression and anxiety symptoms. Total percent weight loss was calculated from pre-WLS and post-WLS weight (kg). Chi-squared analyses and t tests were conducted.

Results: Over a quarter (27.8%) were cannabis-only users and 16.7% used a combination of cannabis and opioids. None reported using only opioids in this sample. Combination users presented with greater depressive symptoms (22.7%, p = 0.01) and greater total percent weight loss (34.1%, p = 0.04) than cannabis users (7.8, 23.2%, respectively). Cannabis users had greater serotonin (p = 0.02) and cortisol (p = 0.01) levels than combination users and never users.

Conclusions: Cannabis users had greater cortisol levels than never users and combination users. Combination users had greater weight loss and depression symptoms than cannabis users. Future studies should consider a larger sample size, utilization of a cohort design to address causality, and examination of the type, dose, and route of cannabis and opioid administration to further understand the impact of the combined use of cannabis and opioids post-WLS.

Keywords: Anxiety; Bariatric surgery; Cannabis; Cortisol; Depression; Duodenum; Gut; Opioids; Serotonin; Weight loss.